PSI's casing spacers/isolators
are used on long distance transmission pipelines for three purposes.
When a pipeline intersects with a railroad right-of-way, highway,
waterway or any other thoroughfare the pipeline usually passes under
or is buried beneath the obstruction. For protection in these areas,
the carrier pipe is placed inside a casing pipe in an effort to
"double contain" the fluid that is passing through the
carrier pipe. If a leak or break were to occur, the fluid would
be directed to a safe distance away from beneath the thoroughfare.
In fact, many local Governmental Agencies require this procedure
almost anywhere when volatile or hazardous fluids are flowing through
the carrier pipe.
Secondly, the casing
spacer/isolator is used to electrically isolate the carrier pipe
from the casing pipe. In most cases a corrosion mitigation program
is in place to protect the carrier pipe from the detrimental effects
of the environmental and surrounding soil. Any outside influence
of stray electrons can render the corrosion mitigation completely
ineffective. A casing spacer/isolator ensures that no metal to metal
contact is made between the carrier pipe and casing pipe which ensures
the integrity of the corrosion mitigation program.
Thirdly, casing spacers
include low coefficient of friction runners on all surfaces making
contact with the casing pipe which facilitates easy insertion of
the carrier pipe into the casing, an especially important feature
when making long pulls/pushes with heavy pipe. PSI's runners have
a tensile strength of 17,600 psi, a flexural strength of 25,300
psi and a compression strength of 18,000 psi.